1. Field of the Invention
The present invention relates generally to Gas Metal Arc Welding (GMAW) or Metal Inert Gas (MIG) welding and, more particularly, to consumable parts for MIG systems, the consumable part otherwise known as contact tips and diffusers.
In MIG type welding a welding wire is utilized to provide a molten metal pool in order to join the metal pieces together. The welding wire in a MIG system is typically protected from atmospheric contamination by a blanket of shield gas. The shield gas is an inert gas or a combination of inert gas plus other gases. MIG welding systems utilize a continuous welding wire that is rolled onto a spool and fed through coaxial welding cable to the welding gun. Because of the continuous welding wire, MIG welding systems are generally faster than Tungsten Inert Gas (TIG) systems or conventional stick welding systems that utilize individual welding rods.
2. Description of the Prior Art
MIG welding systems have been widely used in the United States and other places around the world since at least the 1960's. The present invention is an improvement over these conventional MIG welding systems. The present invention includes improved contact tips and gas diffusers for several types and amperages of MIG welding guns.
An Information Disclosure Statement has been filed concurrently herewith and includes a discussion of the prior art. Some of the individual features found on the present invention can be found in the prior art. For example, on feature, cylindrical contact tips, are well known. However, Applicants believe that some of the individual features are unique. It is common to offer MIG welding guns with various amperage ratings. For example, it is contemplated that embodiments of the present invention will initially be offered in 250 amps., 450 amps., and 600 amps.
There has been a long felt need in the welding industry to increase the operating life of MIG type contact tips. Those skilled in the art will recognize that welding produces a lot of heat. In order to melt the welding wire, the arc point will sometimes reach 10,000.degree. F. (5,000.degree. C.) or more. The molten pool of metal beneath the arc, though cooler, may sometimes reach 5,000.degree. F. (2,760.degree. C.) or more. The contact tip which is typically less than one inch (2.54 cm) away from the arc point may operate at temperatures of approximately 1500.degree. F. (815.degree. C.). Contact tips are typically formed from copper alloys which are adversely effected by high temperatures. Contact tips are also subject to wear because the welding wire feeds through the interior thereof. Contact tips tend to wear out relatively quickly and therefore are replaced many times during the life of a MIG welding gun. Because the tips are replaced so often they are referred to as "consumables" in the industry. The present invention allows the new contact tip to operate at substantially cooler temperatures which is believed to lengthen the overall life of the tip; however, it will still need to be replaced, though not as often.